What we know about certain diseases are still not sufficient to prevent them from spreading easily among the population.

Developing new technologies are time-consuming and expensive.

A novel is a story long enough to fill a complete book, in that the characters and events are usually imaginary.

The leader demanded from his members a serious attitude towards work, good team spirit, and that they work hard.

It is important that cancer is diagnosed and treated as early as possible in order to assure a successful cure. 

People in every part of the world readily and easily communicates by means of electronic mail.

I enjoyed talking to the people with that I met at the party last night. 

The grass needs cutting, so let us have one of the men to take lawn-mower and do it.